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EP0090864A1 - Support d'enregistrement magnetique - Google Patents

Support d'enregistrement magnetique Download PDF

Info

Publication number
EP0090864A1
EP0090864A1 EP82903057A EP82903057A EP0090864A1 EP 0090864 A1 EP0090864 A1 EP 0090864A1 EP 82903057 A EP82903057 A EP 82903057A EP 82903057 A EP82903057 A EP 82903057A EP 0090864 A1 EP0090864 A1 EP 0090864A1
Authority
EP
European Patent Office
Prior art keywords
polymer
recording medium
magnetic recording
magnetic
modified
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Granted
Application number
EP82903057A
Other languages
German (de)
English (en)
Other versions
EP0090864B1 (fr
EP0090864A4 (fr
Inventor
Kaoru Nakajima
Seiichi Miyai
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Sony Corp
Original Assignee
Sony Corp
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Sony Corp filed Critical Sony Corp
Publication of EP0090864A1 publication Critical patent/EP0090864A1/fr
Publication of EP0090864A4 publication Critical patent/EP0090864A4/fr
Application granted granted Critical
Publication of EP0090864B1 publication Critical patent/EP0090864B1/fr
Expired legal-status Critical Current

Links

Classifications

    • G—PHYSICS
    • G11—INFORMATION STORAGE
    • G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
    • G11B5/00—Recording by magnetisation or demagnetisation of a record carrier; Reproducing by magnetic means; Record carriers therefor
    • G11B5/62—Record carriers characterised by the selection of the material
    • G11B5/68—Record carriers characterised by the selection of the material comprising one or more layers of magnetisable material homogeneously mixed with a bonding agent
    • G11B5/70—Record carriers characterised by the selection of the material comprising one or more layers of magnetisable material homogeneously mixed with a bonding agent on a base layer
    • G11B5/702—Record carriers characterised by the selection of the material comprising one or more layers of magnetisable material homogeneously mixed with a bonding agent on a base layer characterised by the bonding agent
    • G11B5/7027—Graft polymers
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
    • Y10S—TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10S428/00—Stock material or miscellaneous articles
    • Y10S428/90—Magnetic feature
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
    • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
    • Y10T428/00—Stock material or miscellaneous articles
    • Y10T428/31504—Composite [nonstructural laminate]
    • Y10T428/31855—Of addition polymer from unsaturated monomers
    • Y10T428/31935—Ester, halide or nitrile of addition polymer

Definitions

  • the present invention relates to a magnetic recording medium and, more particularly, to a magnetic recording medium having a superior durability.
  • the object of the present invention is to provide a magnetic recording medium which has a superior durability by the employment of a binder comprising a modified polymer.
  • the modified polymer binder to be employed in the present invention is produced by the modification of a polymer conventionally used as a binder for magnetic recording media through its graft polymerization with a polymerizable unsaturated compound containing a sulfonic group or a metal sulfonate group through irradiation.
  • a binder may be produced by causing organic free radicals to be generated through exposure of a graft polymerizable polymer to radiation such as gamma rays, electron beams or the like, and thereafter allowing the free radicals to polymerize with the polymerizable unsaturated compounds.
  • the polymer to be modified or a trunk polymer to be employed as a binder in the present invention can be any one which can generate free radicals upon being irradiated and which is not degraded by irradiation. It is to be noted that, since any organic material without exception can produce free radicals if radiation having a high penetrating power is used, and since a polymer likely to be degraded by such radiation can produce enough free radicals to react with the polymerizable unsaturated compound even if the radiation is applied in a small dose under conditions which control degradation, the kind of polymer which can be modified for use with this method extends over a wide range.
  • a polymer to which the aforementioned method can be applied there may be mentioned preferably a polymer having a molecular weight ranging from about 10,000 to about 100,000, such as vinyl chloride-vinyl acetate copolymer, vinyl chloride-vinyl propionate copolymer, vinyl chloride-vinyl acetate-vinyl alcohol copolymer, vinyl chloride-vinyl propionate-vinyl alcohol copolymer, vinyl chloride-vinyl acetate-maleic acid copolymer, vinyl chloride-vinylidene chloride copolymer, vinyl chloride-acrylonitrile copolymer, acrylic ester-acrylonitrile copolymer, acrylic ester-vinylidene chloride copolymer, methacrylic ester-vinylidene chloride copolymer, methacrylic ester-styrene copolymer, thermoplastic polyurethane resin, phenoxy resin, polyvinyl fluoride, vinylidene chloride-
  • the radiation to be used to irradiate the aforementioned polymer for the generation of free radicals may be, for example, gamma rays, an electron beam or the like.
  • the irradiation dose is preferably within the range of about 0.1 to 10 Mrad.
  • the polymerizable unsaturated compound to be graft polymerized with the polymer binder treated by the aforementioned radiation may be any compound having a polymerizable unsaturated bond and a sulfonic group or a metal sulfonate group.
  • unsaturated compounds including an unsaturated sulfoalkyl carboxylic acid such as 2-sulfoalkylmethacrylic acid and so on, an aliphatic sulfonic acid metal salt such as sodium ethylenesulfonate, and an unsaturated compound such as a metal salt of an aliphatic sulfonic acid, e.g., a (metha)acrylamide derivative containing a metal sulfonate group such as 2-acrylamido-2- _ methylpropanesulfonic acid and so on, and a metal salt of an aromatic sulfonic acid such as sodium styrene- sulfonate and so on.
  • unsaturated sulfoalkyl carboxylic acid such as 2-sulfoalkylmethacrylic acid and so on
  • an aliphatic sulfonic acid metal salt such as sodium ethylenesulfonate
  • an unsaturated compound such as a metal salt of an aliphatic
  • Such an unsaturated compound but having an additional substituent different from those aforementioned may also be used as the polymerizable un - saturated compound according to the present invention.
  • the amount of the polymerizable unsaturated compound to the trunk polymer is preferably in the range from 0.1 to 10 parts by weight with respect to 100 parts by weight of the polymer. Where the amount of the polymerizable unsaturated compound is too small, the effect of the sulfonic group and the metal sulfonate group upon being introduced into the polymer on its compatibility with the magnetic powder is so insufficient that dispersibility and packing properties cannot be provided to the desired extent.
  • the modification by reacting the aforementioned. polymerizable unsaturated compound with a conventional polymer binder treated by irradiation. is preferably carried out by the graft polymerization method. Graft polymerization may-be conducted in a conventional manner.
  • the binder comprising the modified polymer to be used in accordance with the present invention can exhibit a sufficient effect in admixture with the aforementioned conventional binder. If the modified binder is used in admixture with the conventional binder, the modified binder must be contained in an amount of at least about 1% by weight based on the total binder amount so that a desired effect may be obtained.
  • the modified polymer binder to be used in accordance with the present invention may be used in a system in which a polyfunctional isocyanate compound is combined or in a thermosetting system in which the conventional binder is combined with the polyfunctional isocyanate compound.
  • the magnetic powder may be any one which is conventionally employed for magnetic recording media. It may be, for example, an oxide magnetic powder such as gamma-Fe203, Fe 3 0 4' iron oxide in an intermediate oxide state between gamma-Fe 2 0 3 and Fe 3 0 4 , Co-containing gamma-Fe 2 O 3 , Co-containing Fe 3 0 4 , Co-containing iron oxide in an intermediate oxide state between gamma-Fe 2 O 3 and Fe 3 0 41 the aforementioned iron oxide containing further one or more metal elements (particularly a transition metal element), the aforementioned iron oxide containing a coating layer composed mainly of a Co oxide or a hydroxide, CrO 2 , Cr0 2 with a Cr 2 0 3 layer formed at the surface area by the reduction treatment, and so forth, and a ferromagnetic fine powder such as a metal such as Fe, Co, Ni and so forth and an alloy such as an Fe-Co alloy, an Fe-Ni alloy, an Fe-Co-Ni
  • a magneticpaint comprising the modified polymer binder according to the present invention and magnetic powder may additionally-contain aluminum oxide, chromium oxide, silicon oxide or the like as an abrasive; carbon black or the like as an antistatic agent; and molybdenum disulfide, graphite, silicone oil, olive oil or the like as a lubricant.
  • a substrate material for a non-magnetic substrate on which a magnetic layer is formed by the magnetic paint comprising the aforesaid composition may be, for example, a polyester such as polyethylene terephthalate or the like, a polyolefin such as polypropylene or the like, a cellulose derivative such as cellulose triacetate, cellulose diacetate or the like, a polycarbonate, a polyvinyl chloride, a polyimide, a metal such as aluminum, copper or the like, paper or the like.
  • a solvent capable of being used for the preparation of the magnetic coating may include, for example, a ketone such as acetone, methyl ethyl ketone, methyl isobutyl ketone, cyclohexanone or the like; an alcohol such as methanol or the like; an ester such as methyl acetate, ethyl acetate, butyl acetate, ethyl butyrate or the like; a glycol ether such as ethylene glycol dimethyl ether, ethylene glycol monoethyl ether, dioxane or the like; an aromatic hydrocarbon such as benzene, toluene, xylene or the like; an aliphatic hydrocarbon such as hexane, heptane or the like; and a mixture thereof or the like.
  • a ketone such as acetone, methyl ethyl ketone, methyl isobutyl ketone, cyclohexanone or the like
  • the magnetic recording medium produced by the aforementioned method can provide a favorable binding effect between the binder and the magnetic powder and eventually between the magnetic powder and the non-magnetic substrate. It also has improved properties in respect of dispersibility and packing properties of the magnetic powder, thereby reducing the amount of rubbing-off-and improving durability.
  • a modified polyurethane binder was prepared by mixing 100 parts by weight of a polyurethane binder (tradename "N-2304"; manufactured by Nippon Polyurethane Kogyo K.K.) with 5 parts by weight of sodium ethylenesulfonate, forming the mixture in a sheet form having a thickness of about 100 u, and irradiating it with an electron beam of 5 Mrad.
  • a polyurethane binder tradename "N-2304"; manufactured by Nippon Polyurethane Kogyo K.K.
  • the paint composition containing the above-mentioned ingredients was milled to give a magnetic paint, and the magnetic paint was coated on a polyester base film having a thickness of 10 P to a thickness of 4 ⁇ . The film was dried and then cut into magnetic tapes.
  • a paint having the following composition was deposited on a polyester base film having a thickness of 16 P to a thickness of 4 P, and magnetic tapes were prepared in the same manner as-in Example 1.
  • the modified polyurethane used in this Example was substantially identical to that used in Example 1.
  • non-modified polyurethane binder (tradename "N-2304") in place of the modified polyurethane binder, magnetic tapes were prepared in the same manner as in Example 1.
  • Magnetic tapes were prepared in the same manner as in Example 2 with the exception that the non-modified polyurethane binder (tradename "N-2304") was used in place of the modified polyurethane binder.
  • N-2304 non-modified polyurethane binder
  • the magnetic tapes prepared according to the aforementioned Examples and Comparative Examples were measured for Bm, Rs, gloss, rubbing-off rating, and still. The results are shown in the following table.
  • gloss was determined with a commercially available gloss meter by measuring an amount of reflected light arising from incident light at an incident angle of 75°. The larger the value thereof, that is, the closer to 100%, the better the surface quality.
  • the rubbing-off rating was determined by an amount of powder attached to a magnetic head, tape guide and so on after running the tape.
  • the durability was defined as the time required for the reduction of output signals from an initial level to a predetermined level by repeated scanning of the same portion of a magnetic tape with the magnetic -head of a household VTR.

Landscapes

  • Paints Or Removers (AREA)
  • Magnetic Record Carriers (AREA)

Abstract

Support d'enregistrement magnétique contenant en tant que liant un polymère modifié préparé par polymérisation à greffe d'un composé polymérisable non saturé possédant un groupe d'acides sulphonique ou un groupe d'un sel métallique de l'acide sulphonique sur un polymère par irradiation avec une radiation. Ce polymère modifié présente de bonnes caractéristiques d'adhésion de la poudre magnétique et améliore les caractéristiques de dispersivité et de remplissage de la poudre magnétique à cause de la présence du groupe d'acides sulphoniques ou du groupe de sels métalliques d'acides sulphoniques. Le support d'enregistrement magnétique possède ainsi une excellente résistance. En outre, étant donné que le polymère modifié peut être obtenu par polymérisation à greffe utilisant une radiation, le polymère à modifier peut être sélectionné à partir d'une gamme étendue de composés, de sorte que le support d'enregistrement magnétique peut être produit par un procédé industriel utilisable dans la pratique.
EP19820903057 1981-10-15 1982-10-15 Support d'enregistrement magnetique Expired EP0090864B1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
JP164667/81 1981-10-15
JP56164667A JPS5864627A (ja) 1981-10-15 1981-10-15 磁気記録媒体

Publications (3)

Publication Number Publication Date
EP0090864A1 true EP0090864A1 (fr) 1983-10-12
EP0090864A4 EP0090864A4 (fr) 1985-04-25
EP0090864B1 EP0090864B1 (fr) 1987-09-16

Family

ID=15797529

Family Applications (1)

Application Number Title Priority Date Filing Date
EP19820903057 Expired EP0090864B1 (fr) 1981-10-15 1982-10-15 Support d'enregistrement magnetique

Country Status (6)

Country Link
US (1) US4520079A (fr)
EP (1) EP0090864B1 (fr)
JP (1) JPS5864627A (fr)
GB (1) GB2119395B (fr)
NL (1) NL8220368A (fr)
WO (1) WO1983001528A1 (fr)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0098885B1 (fr) * 1982-01-14 1989-04-19 Sony Corporation Support d'enregistrement magnetique

Families Citing this family (11)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE3516781A1 (de) * 1984-05-11 1985-11-14 Nippon Zeon Co., Ltd., Tokio/Tokyo Magnetische anstrichfarbe fuer magnetische aufzeichnungsmedien
US4842942A (en) * 1984-08-15 1989-06-27 Toyo Boseki Kabushiki Kaisha Magnetic recording medium
JPS6153368A (ja) * 1984-08-22 1986-03-17 Nippon Zeon Co Ltd 磁性塗料
US4798755A (en) * 1985-05-01 1989-01-17 Fuji Photo Film Co., Ltd. Magnetic recording medium
US4707410A (en) * 1985-09-11 1987-11-17 Nippon Zeon Co., Ltd. Magnetic recording media
US4748084A (en) * 1985-11-11 1988-05-31 Nippon Zeon Co., Ltd. Magnetic recording medium
JPH01195720A (ja) * 1988-01-04 1989-08-07 Nec Corp 半導体集積回路
US5371166A (en) * 1993-12-22 1994-12-06 The B. F. Goodrich Company Polyurethane composition for use as a dispersing binder
US5484063A (en) * 1994-04-13 1996-01-16 Maxtor Corporation HDD carrying case
GB2307872A (en) * 1995-12-04 1997-06-11 Minnesota Mining & Mfg Star polymer binder for magnetic recording materials
US5990218A (en) * 1998-11-20 1999-11-23 The Goodyear Tire & Rubber Company Polymeric magnet compound

Family Cites Families (16)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2207322A1 (en) * 1972-11-22 1974-06-14 Kodak Pathe Magnetic tapes for sound or image recording - contg. copolymer of vinylidene chloride, sulphone cpd. and e.g. acrylonitrile
US3901816A (en) * 1974-06-17 1975-08-26 Dow Chemical Co Magnetic tape coating
JPS5330680A (en) * 1976-09-03 1978-03-23 Toshiba Corp Manufacture of magnetic material composites
JPS6044804B2 (ja) * 1976-12-27 1985-10-05 株式会社東芝 磁性材料複合体成形品の製造法
JPS5841565B2 (ja) * 1978-06-01 1983-09-13 東洋紡績株式会社 磁気記録媒体
JPS5428603A (en) * 1977-08-05 1979-03-03 Toyo Boseki Magnetic recording medium
DE2914659A1 (de) * 1979-04-11 1980-10-23 Agfa Gevaert Ag Magnetisches speichermedium und verfahren zu dessen herstellung
JPS5613524A (en) * 1979-07-12 1981-02-09 Tdk Corp Magnetic recording medium
GB2054622B (en) * 1979-07-12 1983-04-07 Tdk Electronics Co Ltd Magnetic recording medium
JPS5674824A (en) * 1979-11-20 1981-06-20 Hitachi Maxell Ltd Magnetic recording medium
US4415630A (en) * 1980-06-10 1983-11-15 Tdk Electronics Co., Ltd. Process of making magnetic recording medium
JPS5753824A (en) * 1980-09-12 1982-03-31 Fuji Photo Film Co Ltd Magnetic recording medium
JPS5758227A (en) * 1980-09-25 1982-04-07 Tdk Corp Magnetic recording medium
JPH0616324B2 (ja) * 1981-06-10 1994-03-02 富士写真フイルム株式会社 磁気記録媒体
EP0085722A4 (fr) * 1981-08-19 1983-12-23 Sony Corp Resine polymerisable au moyen d'un rayon d'electrons.
US4411957A (en) * 1981-09-03 1983-10-25 Tdk Electronics Co., Ltd. Magnetic recording medium

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0098885B1 (fr) * 1982-01-14 1989-04-19 Sony Corporation Support d'enregistrement magnetique

Also Published As

Publication number Publication date
GB2119395A (en) 1983-11-16
NL8220368A (nl) 1983-09-01
US4520079A (en) 1985-05-28
EP0090864B1 (fr) 1987-09-16
WO1983001528A1 (fr) 1983-04-28
GB8315635D0 (en) 1983-07-13
JPS5864627A (ja) 1983-04-18
GB2119395B (en) 1985-07-17
EP0090864A4 (fr) 1985-04-25

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